In recent years, accompanying a rapid increase in traffic, communication devices performing communication via a wireless LAN (Wireless Local Area Network (WLAN)) communication scheme are increasing. The WLAN communication scheme is, for example, a communication scheme based on IEEE 802.11 specifications and is a communication scheme in which communication is performed without synchronization between the devices.
For example, a first communication device (for example, a network-side node) transmits first information (for example, user data) to a non-synchronized second communication device (for example, a radio terminal) via the WLAN communication scheme. After normally receiving the data, the second communication device transmits, after a shortest wait time (SIFS (Short InterFrame Space) time) has elapsed, second information (for example, an ACK) to the first communication device, in response to the reception of the data.
It is assumed that an existing WLAN communication scheme is used when performing a communication of one-to-one. Therefore, it is not assumed that the first communication device receives the second information from a plurality of second communication devices.